1. Field of the Invention
The present invention relates generally to surgical instruments for occluding a vessel or other tubular structure, for grasping and retaining other body tissue, for retracting tissue at a surgical incision site, or for stabilizing tissue or bodily organs within a surgical incision site. More particularly, the invention relates to surgical instruments such as surgical clamps, surgical retractors or surgical stabilizers that include resilient filaments that abut against a vessel, tissue or organ to resist movement of the vessel, tissue or organ relative to the instrument. The invention further relates to methods of manufacturing clamp pads or members for attachment to such instruments that include such resilient filaments.
2. Description of the Related Art
Instruments for occluding blood vessels during surgery, such as conventional metal or rigid surgical clamps or clips, are well known. However, such instruments are known to cause trauma to the clamped vessel at the clamping site. A number of atraumatic instruments have been developed for reducing or eliminating the trauma to a vessel during occlusion of the vessel. U.S. Pat. No. 3,993,076 to Fogarty, et al. describes a device whereby a vessel is occluded by using a resilient tape to press a vessel against a resilient pad. However, this device suffers from the disadvantage that it slips easily. For example, the pulsations of an occluded artery can tend to force the device off of its clamped position on the occluded artery. Conventional surgical clamps have also been adapted to include jaw surfaces containing resilient members or pads. These devices likewise are prone to slipping off of the clamped vessel. This can be especially problematic in situations where, due to obstructions, a vessel has been clamped with only the distal tips of the clamp jaws. In such situations, the vessel can be especially prone to slipping in the direction of the distal tips.
Other attempts have been made to atraumatically occlude a vessel in a secure fashion. U.S. Pat. No. 3,746,002 to Haller describes a vascular clamp with resilient gripping members located on the jaws. A plurality of pin members are embedded within the gripping members, the pin members of a length such that when a vessel is clamped between the members, the resilient material deflects to accommodate the vessel, exposing the pin members which grippingly engage the outer layer of the vessel, thus securing the vessel to the gripping member. While the Haller device is less traumatic to a vessel than other occlusion devices, it nevertheless has the disadvantage of traumatizing the outer layer of the vessel.
U.S. Pat. No. 4,821,719 to Fogarty describes a vascular clamp device containing resilient pads with Velcro-like hooks. The hooks interact with the external adventitial layer of the vessel forming a cohesive-adhesive relationship with the vessel similar to the bonding of Velcro materials. While this device offers a less traumatic way to occlude a vessel, the cohesive-adhesive nature of the bond can result in the removal of some of the adventitial layer of the vessel when disengaging the device.
There is thus a need for a surgical clamp which atraumatically occludes vessels while avoiding the disadvantages previously associated with existing surgical clamps or occlusion devices.
Likewise, conventional tissue retractors are well known which retract tissue at a surgical incision site to provide a surgeon visual and mechanical access to the interior of a patient's body. These tissue retractors employ rigid gripping members, usually of metal, to grip, retract, and retain all forms of body tissue, e.g., bone, skin, fat, or muscle, at the incision site. The disadvantages of such retractors are two-fold. First, the rigid gripping members, due to their rigidity, cause trauma to the retained tissues. Second, the gripping members are generally prone to slippage, both laterally, along the sides of the incision, and upwardly out of the incision and away from the patient's body.
Thus, there is also a need for a surgical retractor that atraumatically, yet securely, retracts and retains tissue at a surgical incision site.
Other surgical instruments or devices are known that provide for mechanical immobilization and stabilization of tissue or organs within a surgical incision site. These instruments or devices, known as stabilizers, will immobilize, stabilize, or otherwise restrain tissue or organs by exerting pressure against a tissue or organ to hold the tissue or organ in place, aiding a surgeon performing operations on the tissue or organ. Such stabilizers have particular use in minimally invasive coronary surgery procedures. For example, coronary artery stabilizers have been used to immobilize a beating heart in order to perform coronary grafting. These stabilizers achieve immobilization largely by local myocardial compression from direct pressure applied by the stabilizer on either side of the grafted artery. These stabilizers come in a variety of shapes, including open foot-shaped devices, and rigid circle or rectangular shapes, and may be either hand held, or attached to an incisional retractor located at the incision site. Another such stabilizer device consists of a system having two fixed handles having suction cups that are positioned on either side of the vessel.
Given the amount of pressure transferred to the myocardium during the use of these stabilizers, there is a danger that the contact surfaces of these stabilizer devices will traumatize the myocardial tissue. In addition, the forces exerted by the immobilized but still beating heart can lead to a shift in alignment of the stabilizer, which can disrupt the grafting procedure. Thus, there is a need for stabilizers that atraumatically immobilize a tissue or body organ, such as the heart, and yet at the same time provide improved traction to maintain the position of the immobilized tissue or organ.